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PowerShell global variable not retrieved correctly

See original GitHub issue

Variables are defined at the beginning of the PowerShell script; without the “global” keyword Assuming these variables are in global scope.

$accessTokenTest = ""`
$accessToken = ""`

Here is a function to renew the SQL access token and persist it to a JSON file. In Get-SQLToken function, global variables were saved differently, with and without “global” keyword. This was the workaround for the issue: $Global:accessToken = $tokenResponse.access_token

function Get-SQLToken {
    WriteToLog -message "Token Start..."
    try {
        $resourceURI = "https://database.windows.net/"
        $tokenAuthURI = $env:MSI_ENDPOINT + "?resource=$resourceURI&api-version=2017-09-01"
        $tokenResponse = Invoke-RestMethod -Method Get -Headers @{"Secret" = "$env:MSI_SECRET" } -Uri $tokenAuthURI
        WriteToLog -message "Create new SQLSetting file"
        $tokenResponse | ConvertTo-Json | Out-File SQLSettings.json
        $Global:accessToken = $tokenResponse.access_token
        $accessTokenTest = $tokenResponse.access_token
        if ($null -eq $accessTokenTest || [string]::IsNullOrEmpty($accessTokenTest)) {
            WriteToLog -message "[DBG] Failed to save access token value to a global variable. accessTokenTest is $($accessTokenTest)"
        }
        else {
            WriteToLog -message "[DBG] Successfully save access token value to a global variable accessTokenTest. accessTokenTest is $($accessTokenTest)"
        }
    }
    catch [System.Exception] {
        WriteToLog -message "Error occured $($_.Exception.Message)" -Exception $_
        $tokenResponse = ""    
    }
    WriteToLog -message "Token end"
}

We retrieve the value of the global variables later on.
However, the variable $accessTokenTest was not retrieved correctly

   $SQLSettings = Get-Content SQLSettings.json | ConvertFrom-Json
    if ([datetime]$SQLSettings.expires_on -gt ((Get-Date).AddHours(23))) { # DBG AddMinutes(30)
        $accessToken = $SQLSettings.access_token
        WriteToLog -message "Token from SQLSettings"
    }
    else {
        WriteToLog -message "Old Token need a new Token... create new SQLSettings"
        Get-SQLToken
        if ($null -eq $accessTokenTest || '' -eq $accessTokenTest || [string]::IsNullOrEmpty($accessTokenTest)) {
            WriteToLog -message "[DBG] Failed to retrieve token value from a global variable. accessTokenTest is $($accessTokenTest)"
        }
        else {
            WriteToLog -message "[DBG] Successfully retrieved token value from a global variable accessTokenTest. accessTokenTest is $($accessTokenTest)"
        }
        $accessToken = $Global:accessToken
    }

In order to work around the hurdle, we applied the work around which seems redundant.

Save the value to the global variable $accessToken with global keyword

$Global:accessToken = $tokenResponse.access_token

Retrieve the value of the global variable $accessToken with global keyword

$accessToken = $Global:accessToken

From the logs,
2022-08-06T23:42:54.398 [Information] INFORMATION: [DBG] Successfully save access token value to a global variable accessTokenTest. accessTokenTest is<<value is redacted>>
no value got retrieved, or no printable value got retrieved
2022-08-06T23:42:54.399 [Information] INFORMATION: [DBG] Successfully retrieved token value from a global variable accessTokenTest. accessTokenTest is<<end of line>>

We have been running this script without work around since August 2021 under PowerShell 7 kernel until the issue started surfacing in early March this year. We would like to learn: